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View Full Version : Need help Win 8.1 will not boot missing BCD



Humungus1138
07-15-2015, 06:21 PM
Fellow ROGs,

Need your help. Recently upgraded my old G60 for a new new G751. I had upgraded my G60 with an SSD running Win 7 Pro so I wanted to put that in my
second drive slot and dual boot between 8 and 7. I also have E asyBCD which I thought might help. Well it took me a while to figure out how to get the 751 bios to see my
new disk as a potential boot drive. After tweaking a few BIOS things it did and I got the option from Win 8 to boot either (I was not running BCD yet). However, when I attempted to run
Win 7 it would not load.

A while later I determined that I had to turn off secure boot. Once I did this found that I could dual boot using the BIOS boot manager (pressing the ESC key)

THat was good but not exactly what I wanted so at this point I went into 8 and used EasyBCD to try to get things to work right in 8.

along the way I must have screwed something up because now my machine is in a state where I can only boot from the BIOS manager and I
can only boot win 7. If I select my win 8 drive it tells me there is no valid BCD entry there.

I have tried adding a new boot record to restore win 8 but so far nothing has worked. I have not touched the drive that Win 8 was on except
to try and get EasyBCD to work. At some point I think it reset the BCD info on this drive.

Does anyone know how to correct this from BIOS? I cannot get into Win 8 to fix this

TIA

Roger

OneMoar
07-15-2015, 11:58 PM
congrads you managed to toast the bootloader
now you need to format and reinstall
you could try booting from the windows install media and from a recovery command prompt and run these commands
bootrec /fixboot
bootrec /fixmbr
bootrec /rebuildbcd

Clintlgm
07-16-2015, 03:43 AM
Sounds like you don't understand UEFI, your old Win 7 SSD is most likely BIOS MBR by turning off secure boot and enabling CSM that allowed you to boot the old win 7 SSD but trashed your windows 8 UEFI GPT disk.
BIOS MBR and UEFI GPT are not compatible for Operation Systems. I would suggest pulling out the Win 7 SSD, Set your BIOS back to UEFI if you change it. Turn back on secure Boot and use a Windows 8.1 bootable USB or DVD and run a Repair install you may have to run the repair several times for it to complete repairing your Boot Files. One thing to look for if your somehow converted your Windows 8.q to MBR your not likely to get it booting and will need to reinstall get your ISO Here (http://windows.microsoft.com/en-us/windows-8/create-reset-refresh-media) go to the eight forum for step by step tutorial (http://www.eightforums.com/gtsearch.php?cx=partner-pub-7156303416008077%3A205v6qk06j2&cof=FORID%3A9&ie=UTF-8&q=HOw+to+install+UEFI) Once you get win 8.1 running again if your still want to run a dual boot with win 7 do a clean install of win 7 UEFI mode. You really don't need Win 7 for anything though just install Classic Shell (http://www.classicshell.net/)and configure it to run just like win 7 or Xp if you want to. All the hot corners go away you boot up to your log in screen from there to your desktop just like you always have.

clockworksatan
07-16-2015, 07:21 AM
You really don't need Win 7 for anything though just install Classic Shell (http://www.classicshell.net/)and configure it to run just like win 7 or Xp if you want to. All the hot corners go away you boot up to your log in screen from there to your desktop just like you always have.

Exactly what I was thinking. You've just made your life more difficult because Windows 7 doesn't offer anything that Windows 8.1 does. Ok, so you have to deal with the clunky 8.1 UI, but with 10 just around the corner I really don't see the point in dual-booting 7 & 8.

However, it definitely sounds like you're going to have to do a clean install of 8.1 which is actually dead easy to do as the serial number is embedded in your BIOS, so it's just a case of downloading 8.1 and running through the installer. You can download it here (http://windows.microsoft.com/en-us/windows-8/create-reset-refresh-media). Once you're back on your feet, the drivers are easy to downoad from the Asus site here (https://www.asus.com/uk/Notebooks_Ultrabooks/ASUS_ROG_G751JT/HelpDesk_Download/) (I would recommend doing that and burning them to a disk/USB drive in advance of starting to install 8.1) and, as I just did it myself recently, I would recommend that you install them in the correct order following the guide here (https://rog.asus.com/forum/showthread.php?58411-Guide-The-G751-new-user-thread-(Clean-install)).

Then do a backup using Macrium Reflect (http://www.macrium.com/reflectfree.aspx) and you're sorted.